The present invention is directed, in general, to wireless communication systems and, more specifically, to a system for monitoring the signal integrity of interconnections in a modular base station in a wireless communication network.
Wireless communication systems, including cellular phones, paging devices, personal communication services (PCS) systems, and wireless data networks, have become ubiquitous in society. Wireless service providers continually try to create new markets for wireless devices and to expand existing markets by making wireless devices and services cheaper and more reliable. The price of end-user wireless devices, such as cell phones, pagers, PCS systems, and wireless modems, has been driven down to the point where these devices are affordable to nearly everyone and the price of a wireless device is only a small part of the end-user""s total cost. To continue to attract new customers, wireless service providers concentrate on reducing infrastructure costs and operating costs while improving quality of service in order to make wireless services cheaper and better.
In order to increase the number of subscribers that can be supported in a single wireless network, wireless service providers often maximize frequency reuse by making individual cell sites smaller and using a greater number of cell sites to cover the same geographical area. Accordingly, the greater number of base stations increases infrastructure costs, operating costs, and maintenance costs. To offset these increased costs, wireless service providers are eager to implement any innovations that may reduce equipment costs, maintenance and repair costs, and operating costs, or that may increase service quality.
Conventional wireless networks contain xe2x80x9cintegratedxe2x80x9d base stations in which RF (or radio) functions and non-RF (non-radio) functions are performed within the same physical assembly. RF functions include the transmission, reception, modulation, demodulation, amplification, and filtering of inbound and outbound signals. Non-RF functions include signal processing and switching of low-frequency signals, such as baseband and intermediate frequency (IF) signals. In integrated base stations, the RF signal transmitted by the base station may be directly monitored by built-in test equipment, such as a dedicated test equipment circuit board, installed in the chassis of the base station. The measured RF signal parameters may then be transmitted to a central monitoring facility, such as a mobile switching center, along with the normal voice and data traffic associated with the calls handled by base station.
Recently, however, base stations have been implemented in modular and distributed architectures, rather than as integrated units. In some modular and distributed designs, RF functions are implemented in one module and non-RF functions are implemented in a separate module remote from the RF functions module. One such modular and distributed base station is disclosed in U.S. Provisional Patent Application Serial No. 60/058228, filed on Sep. 9, 1997, and in U.S. patent application Ser. No. 09/149,168, filed on Sep. 8, 1998, both of which are assigned to Samsung Electronics Co., Ltd., the assignee of the present application. The teachings of U.S. Provisional Patent Application Serial No. 60/058228 and U.S. patent application Ser. No. 09/149,168 are hereby incorporated by reference into the present application as if fully set forth herein. The Pico-BTS(trademark) system provided by Samsung Electronics Corporation incorporates a modular and distributed base station design in which RF functions are implemented in a radio unit (RU) and non-RF functions are implemented in a separate modular non-radio unit or main unit (MU).
The advantages of a modular and distributed design are many. This design results in a compact radio unit that can be mounted close to the antennas, thereby greatly reducing cable losses in the inbound and outbound RF signals. The separation of RF and non-RF elements results in easier adaption of the modular and distributed design to different RF operating conditions. If the radio unit is upgraded or replaced, it is not necessary to simultaneously upgrade or replace the main unit, and vice versa. For example, if a single non-radio main unit supports three radio units in a three sector antenna system and the main unit is replaced in order to upgrade the signal processing capability of the main unit, the three radio units are not affected. In an integrated base station, the radio units would be discarded along with the outdated main unit.
In some cases, the separation of the base station into separate modular units, such as a non-radio (main) unit and a radio unit, may make the process of monitoring and trouble-shooting the operation of the base station more difficult. Important signals that could be accessed from a single test connector in an integrated unit now are divided between two modular units. If a base station fails, one or both of the assemblies housing the main unit and the radio unit may have to be opened in order to measure the characteristics of particular signal(s) or to inject selected signals during the trouble-shooting process. This can be especially time consuming, costly, and hazardous if the radio unit is mounted with the antenna at the top of a utility pole.
Therefore, there is a need in the art for systems and methods that allow important signals to be easily monitored in a modular base station comprising a main (or non-radio) unit and a radio unit. There is a further need in the art for systems and methods which allow important signals to be monitored without having to open up the assemblies housing the base station modules.
To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide a test apparatus for use in a wireless network base station comprising a non-radio unit capable of processing baseband signals and a radio unit separate from the non-radio unit capable of transmitting and receiving radio frequency (RF) signals. In an advantageous embodiment of the present invention, the test apparatus comprises: 1) a housing; 2) a first connector associated with the housing and capable of being coupled to a first cable coupled to the radio unit, wherein the first cable comprises a first plurality of signal lines carrying a plurality of base station signals between the radio unit and the non-radio unit; 3) a second connector associated with the housing and capable of being coupled to a second cable coupled to the non-radio unit, wherein the second cable comprises a second plurality of signal lines carrying the plurality of base station signals between the radio unit and the non-radio unit; and 4) a first access connector capable of allowing a signal measuring device to monitor at least one of the plurality of base station signals.
According to one embodiment of the present invention, the test apparatus further comprises a second access connector capable of allowing a first test signal to be injected into the radio unit via the first cable.
According to another embodiment of the present invention, the test apparatus further comprises a first switch capable of coupling a first selected one of the first plurality of signal lines to a second selected one of the second plurality of signal lines when the first switch is in a first switch position.
According to still another embodiment of the present invention, the first switch is further capable of coupling the first selected one of the first plurality of signal lines to a test point on the second access connector when the first switch is in a second switch position.
According to yet another embodiment of the present invention, the test apparatus further comprises a third access connector capable of allowing a second test signal to be injected into the non-radio unit via the second cable.
According to a further embodiment of the present invention, the second test signal is injected into the non-radio unit via the second cable when the first switch is in the second switch position.
According to a still further embodiment of the present invention, the first access connector is capable of allowing a test signal to be injected into the non-radio unit via the second cable.
According to a yet further embodiment of the present invention, the test apparatus further comprises an indicator light associated with the housing.
In one embodiment of the present invention, the indicator light is coupled to at least one of the first plurality of signal lines and illuminates to indicate the presence of a first selected one of the base station signals.
In another embodiment of the present invention, the first selected base station signal is a power supply voltage.
The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
Before undertaking the DETAILED DESCRIPTION OF THE INVENTION, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms xe2x80x9cincludexe2x80x9d and xe2x80x9ccomprise,xe2x80x9d as well as derivatives thereof, mean inclusion without limitation; the term xe2x80x9cor,xe2x80x9d is inclusive, meaning and/or; the phrases xe2x80x9cassociated withxe2x80x9d and xe2x80x9cassociated therewith,xe2x80x9d as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term xe2x80x9ccontrollerxe2x80x9d means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.